Temperature Effect on Bonding and Debonding Behavior between FRP Sheets and Concrete

Bond-Slip Model for FRP Laminates Externally Bonded to Concrete at Elevated Temperature

“…20, 40, 55 and 70 o C). The ultimate load of the FRP-to-concrete bonded joint was found in this study to increase by 41% and 24% when the temperature was increased from 20 Similar double-lap shear tests were carried out by Wu et al (2005) on concrete specimens bonded with carbon fabric sheets. The wet lay-up FRP laminates were formed in two steps: a primer layer was first applied to the concrete surface, followed by the impregnation and placement of the fabric sheets with an epoxy resin.…”

“…It should be noted that in most existing tests of FRP-to-concrete bonded joints at elevated temperature, strain readings were not taken during the heating process; that is, the reported strain readings did not include the initial strains in the FRP laminate induced by thermal incompatibility between FRP and concrete (Blontrock 2003;Wu et al 2005;Leone et al 2009). Therefore, when such data are used in regression analysis, the initial thermal strains need also be eliminated from the predicted strains.…”

“…The test data of 79 bonded joint shear tests conducted at ambient and elevated temperatures were assembled from the existing experimental studies reviewed earlier (Blontrock 2003;Klamer 2006;Wu et al 2005;Cai 2008;Leone et al 2009) to examine the dependence of and on temperature following the approach explained above. All these test results were from double-lap shear tests with a sufficient FRP bond length.…”

“…Details of all the specimens and their test results are shown in Table 1. In the tests of Cai (2008) and Lenoe et al (2009), the values (including both , and , ) were determined by the researchers using the differential scanning calorimetry (DSC) method, while in the tests of Blontrock (2003), Wu et al (2005) and Klamer (2006), the values were provided by the material suppliers. In the case of FRP sheets, as the bonding adhesive is also used as the polymer matrix, the values of , and , are usually identical.…”

“…; Specimens C-S-20 to G-S-80 are from Leone et al (2009); Specimens O-26 to T-60 are from Wu et al (2005); Specimens B1-20 to B2-90 are from Klamer (2006); Specimens CS-4 to CS-180 are from Cai (2008). Note that specimens B1-20 to B1-100 were prepared with normal strength concrete whereas specimens B2-20 to B2-90 were prepared with high strength concrete.…”